Shampoo compositions for cleaning hair which also contain conditioning agents are well known. Among the preferred types of conditioning agents are nonvolatile, insoluble, fluid conditioning agents such as polydimethylsiloxane and other silicone polymers. Silicone conditioners are particularly valued for their ability to provide a smooth, soft feel to dry hair. Other common insoluble fluid conditioners include organic fluids, e.g. oils, such as hydrocarbons and fatty esters. These conditioners are valued for their ability to replace natural oils lost from the hair due to cleansing surfactants in shampoos, and to add sheen and luster to the hair. In order for these types of shampoos to be effective and to provide a consistent level of performance, without necessitating vigorous shaking of the package in which they are contained, it is necessary to suspend them in the composition with the aid of a suspending agent. Furthermore, since shampoos are likely to remain on shelves or in storage for long periods of time, it is important for the suspending agents to keep the conditioning agents well suspended for long periods of time. The suspending agents which are preferred for suspension of insoluble, dispersed phase fluid conditioning agents are those which form a crystalline network in the shampoo when not exposed to shear, such as when the shampoo is being stored on the shelf, but which allow the composition to be readily flowable when shear is applied, such as when a user tilts a bottle of the shampoo in preparation to dispense a portion of it onto ones hand or hair. Examples of such suspending agents include ethylene glycol distearate and N, N-di-(hydrogenated tallow) amido benzoic acid.
Just as important as suspending the insoluble, dispersed phase fluid conditioning agents, the suspending agent must also allow the conditioning agent to deposit on the hair or scalp during use. If the conditioning agent does not deposit well, large proportions will likely be rinsed away and, therefore, the shampoo will be unable to provide good conditioning efficacy. Alternately, in order to provide good conditioning, relatively high levels of the conditioning agents would need to be incorporated into the shampoo composition. This would add additional cost to the product, reduce lathering, and present additional product stability concerns.
Obtaining good deposition of the conditioning agent is further complicated by the action of detersive, i.e. "cleaning", surfactants in the shampoo. Detersive surfactants are designed to carry away, or remove, oil, grease, dirt, and particulate matter in general from the hair and scalp. In addition, the detersive surfactants will interfere with deposition of the dispersed phase fluid conditioning agent, and carry away both non deposited and some deposited conditioning agent during rinsing. This effect makes effective deposition of the conditioning agent even more critical for providing efficacious, cost effective conditioning from a shampoo matrix.
Another important parameter in the formulation of conditioning shampoos is lathering. The consuming public often associates high lathering with effective cleaning, and prefers high lathering shampoos from an aesthetic standpoint. Unfortunately, crystalline suspending agents, which are highly effective at suspending insoluble dispersed phase fluid conditioning agents, also tend to adversely affect lathering performance. In addition, these types of conditioning actives themselves also reduce the ability of the shampoo to provide good lather. It has become conventional practice to enhance the lathering performance of these shampoos by increasing the level of, or adding, ingredients that promote high lathering. Common ingredients for this purpose include increased levels of alkyl sulfate surfactants, the addition or increase in the level of betaine amphoteric surfactants, and the addition of fatty ester (e.g. C.sub.10 -C.sub.22) mono- and di- (C.sub.1 -C.sub.3) alkanol amide foam boosters.
It has been found, however, that these ingredients which enhance lathering performance also decrease deposition of insoluble dispersed phase fluid conditioning agents from the shampoo matrix.
It is an object of this invention to provide high lathering conditioning shampoos containing suspended, insoluble, dispersed phase fluid conditioning agents which provide improved deposition of insoluble dispersed phase fluid conditioning agents.
This and other benefits of the present invention as may be or become apparent to one skilled in the art can be obtained according to the present invention, as described in the description which follows.
Unless otherwise indicated, all percentages are calculated by weight of the total composition, and all ratios are calculated on a weight basis. Unless otherwise indicated, ingredients are based on the active level and, therefore do not include carriers or by-products that may be included in commercially available materials.